The present invention relates to quarter-turn ball valves with an improved coupling between the ball and stem.
Typical ball valves have a housing which includes an axially extending fluid communication path and a ball receiving chamber into which a ball element of the valve is inserted. The valve body also includes an opening extending orthogonally to the flow path for receiving a stem which typically includes a locking flange, such that the stem can be inserted through the stem aperture from the ball valve chamber and the ball subsequently loaded into the chamber with interlocking tongue and groove members for coupling the stem and ball. Some ball valve proposals allow the stem to be inserted from the outside of the valve body. Such construction requires a locking flange within the valve body and/or a retainer on the stem to retain the stem in locked position with respect to the valve body. Both of these types of systems are either somewhat difficult to assemble and/or result in more complicated structures for manufacturing. Thus, there exists a need for a ball valve which is both economical to manufacture and which is easy to assemble.